Messages in this thread | | | Date | Wed, 15 Apr 2015 16:07:03 +0530 | From | Preeti U Murthy <> | Subject | Re: [PATCH 2/3] sched, timer: Use atomics for thread_group_cputimer to improve scalability |
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On 04/15/2015 04:39 AM, Jason Low wrote: > /* > @@ -885,11 +890,8 @@ static void check_thread_timers(struct task_struct *tsk, > static void stop_process_timers(struct signal_struct *sig) > { > struct thread_group_cputimer *cputimer = &sig->cputimer; > - unsigned long flags; > > - raw_spin_lock_irqsave(&cputimer->lock, flags); > - cputimer->running = 0; > - raw_spin_unlock_irqrestore(&cputimer->lock, flags); > + WRITE_ONCE(cputimer->running, 0);
Why do a WRITE_ONCE() here ? Maybe you should explicitly mention this through a comment like Steven pointed out about all WRITE/READ/ACCESS_ONCE() usage.
Regards Preeti U Murthy > } > > static u32 onecputick; > @@ -1114,9 +1116,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk) > if (sig->cputimer.running) { > struct task_cputime group_sample; > > - raw_spin_lock(&sig->cputimer.lock); > - group_sample = sig->cputimer.cputime; > - raw_spin_unlock(&sig->cputimer.lock); > + sample_group_cputimer(&group_sample, &sig->cputimer); > > if (task_cputime_expired(&group_sample, &sig->cputime_expires)) > return 1; >
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